Role of Mg2+ block of the inward rectifier K+ current in cardiac repolarization reserve: A quantitative simulation

Ishihara, Keiko; Sarai, Nobuaki; Asakura, Kiyoshi; Noma, Akinori; Matsuoka, Satoshi

doi:10.1016/j.yjmcc.2009.03.008

Cited by 29 publications

(42 citation statements)

References 49 publications

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“…The temporal increase in I K1 conductance during phase 3 repolarization was demonstrated in a series of elegant studies (Ishihara et al, 2009;Ishihara and Yan, 2007;Yan and Ishihara, 2005), and mechanisms of this I K1 transient was attributed to the time-dependent kinetics of I K1 . Indeed, the present simulation protocol of EAD (Fig.…”

Section: Role Of the I K1 Transient In Generating Eadmentioning

confidence: 96%

“…Finally, I K1 is almost completely relieved from the Mg 2þ blockage to provide more than 95% of final repolarizing current. Ishihara et al (2009) demonstrated that this inward rectifying property is time-dependent because of spermine block, which competes with the V m -dependent Mg 2þ -block (see Fig. 8 inset for the kinetic scheme).…”

Section: Ead Evoked By Retarding the I Nal Inactivation With Or Withomentioning

confidence: 96%

“…8A, the I K1 transient has two opposing influences on phase 3 repolarization; the rising phase of the I K1 transient accelerates repolarization, and the subsequent falling phase decelerates or even inverts the AP repolarization to depolarization. Ishihara et al (2009) described the former influence of I K1 as a component of the repolarization reserve. In addition, they found that even an EAD was generated if the I K1 transient was depressed by modifying the intracellular spermine/Mg 2þ ratio under pharmacological I Kr depression.…”

Section: Role Of the I K1 Transient In Generating Eadmentioning

confidence: 99%

See 2 more Smart Citations

EAD and DAD mechanisms analyzed by developing a new human ventricular cell model

Asakura

Cha

Yamaoka

et al. 2014

Progress in Biophysics and Molecular Biology

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Section: Role Of the I K1 Transient In Generating Eadmentioning

confidence: 96%

Section: Ead Evoked By Retarding the I Nal Inactivation With Or Withomentioning

confidence: 96%

Section: Role Of the I K1 Transient In Generating Eadmentioning

confidence: 99%

See 1 more Smart Citation

EAD and DAD mechanisms analyzed by developing a new human ventricular cell model

Asakura

Cha

Yamaoka

et al. 2014

Progress in Biophysics and Molecular Biology

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“…Myocardium, reduced Mg levels could represent a common link between these adverse cardiovascular events. Several recent studies also demonstrated an association of low serum Mg level and increased risk of atrial fibrillation and sudden cardiac death using a mathematical model of a cardiac ventricular myocyte [39] [40].…”

Section: Discussionmentioning

confidence: 92%

Alterations in Low-Z Elements Distribution in Heart Tissue after Treatments to Breast Cancer Using LEXRF Technique

Mantuano¹,

Barroso²,

Nogueira³

et al. 2016

AJAC

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Data from Global Cancer Statistics show that breast cancer (BC) is the most common type of cancer among women, leading the number of deaths caused by cancer. The developments in diagnosis and treatment techniques for the BC, including chemotherapy and/or radiotherapy, increased the survival rates for this type of cancer. One late complication induced by BC treatment is the cardiotoxicity. This term comprises different cardiotoxic side effects, which include blood pressure alterations, myocardial ischemia, congestive heart failure and other damages. This study aimed to evaluate the cardiac alterations induced by radiotherapy and chemotherapy, simulating a treatment for BC in Wistar rats. It is, therefore, important to understand the mechanisms involved in the cardiotoxicity, in order to prevent women from this late effect, when they undergo BC treatments. The major interests in this work are in Low atomic weight elements as Sodium, because it is strongly related to cardiomyocyte contraction; Magnesium, because it is important in the cardiac metabolism; and Iron, because BC treatment induced cardiotoxicity can be associated to the oxidative stress. Changes that occur in unhealthy tissues in case to cardiovascular damages can be better understood when elemental compounds and structures of healthy tissues are known. Low Energy X-ray Fluorescence (LEXRF) technique was used to obtain elemental maps of low Z-elements providing a semi-quantitative analysis of the tissues evaluated under different conditions. Through the technique LEXRF we obtained elemental and absorption maps. The results showed more damages when associating chemotherapy and radiotherapy in comparison to myocardium healthy. Those images taken together with light microscopy, X-ray absorption and phase How to cite this paper: Mantuano, A., Barroso, R.C., Nogueira, L.P., Colaço, M.V., Mota, C.L., Pickler, A., Braz, D., Salata, C., Ferreira-Machado, S., de Almeida, C.E. and 755contrast images, satisfactorily characterize the cardiac tissue for the first time in the literature, from the structural and morphological points of view. LEXRF was carried out at TwinMic beamline in the ELETTRA Synchrotron Facility, at the beamline TwinMic, in Trieste, Italy.

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“…These changes in ECG parameters in hypomagnesemia would be causally related to, in part, the loss of a naturally occurring Ca 2+ antagonist in serum in the condition. In addition, intracellular Mg 2+ has been shown to block outward movement of K + through the inward rectifier K + channel [15,16]. Therefore the effects of Mg deletion on ECG can be attributed to its loss of blocking effects on Ca 2+ and K + channels involved in the genesis of the action potentials in sinoatrial node, atrial and ventricular cells [17,18].…”

Section: Discussionmentioning

confidence: 99%

Hypomagnesemic down-regulation of L-type Ca2+ channel in cardiomyocyte as an arrhythmogenic substrate in rats

et al. 2015

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Role of Mg2+ block of the inward rectifier K+ current in cardiac repolarization reserve: A quantitative simulation

Cited by 29 publications

References 49 publications

EAD and DAD mechanisms analyzed by developing a new human ventricular cell model

EAD and DAD mechanisms analyzed by developing a new human ventricular cell model

Alterations in Low-Z Elements Distribution in Heart Tissue after Treatments to Breast Cancer Using LEXRF Technique

Hypomagnesemic down-regulation of L-type Ca2+ channel in cardiomyocyte as an arrhythmogenic substrate in rats

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